Using Biosolids to Increase the Sustainability of Sod Production.

The amount of biosolids created by municipal wastewater facilities continues to grow each year, while close proximity land that is suitable for biosolids application is increasingly difficult to find.  Also, sod growers in recent years have been dealing with rising production costs that have reduced profitability.  Using biosolids to supply turfgrass nutrients for sod production can help alleviate both of these issues. The purpose of this study is to determine the agronomic benefits or drawbacks to using a biosolids-based sod production system compared to a traditional production system, quantify the annual soil loss or gain during conventional and biosolids-based sod production and harvest, determine short and long-term impacts of using biosolids for sod production on soil physical and chemical properties and, determine the effects of a biosolids-based sod production system on disease, weed, and insect pest pressures.  Two biosolids products from the Alexandria Sewer Authority, a class A dewatered cake and the same material blended with wood fines, were used at three different rates (1.5x, 1.0x and .5x) and compared to a control treatment that follows conventional sod production methods using synthetic fertilizer.  Plots were established fall 2009 in a Kentucky bluegrass (Poa pratensis) and tall fescue (Festuca arundinacea) mixture.  Turfgrass quality, density and color were tracked through establishment in fall 2009 and spring 2010.  Initial data show that the biosolids applied at 1.5 times the annual turfgrass nitrogen demand resulted in significantly higher turfgrass density and color compared to plots receiving just the annual nitrogen demand (300 kg N ha^-1).  Data also indicate that the biosolids applied at the annual nitrogen demand had similar results to conventional treatments using synthetic fertilizers.  Sod tensile strength and soil loss during harvest data will be collected summer 2010.